Storage phosphor radiography patient identification system

ABSTRACT

A storage phosphor radiography patient identification system which matches a patient with an x-ray image of the patient stored in a storage phosphor. The system includes a patient identifying bar code - uniquely identifying a patient; a storage phosphor identifying bar code uniquely identifying a storage phosphor and a portable bar code scanner. The bar code scanner is used to scan the patient bar code and the storage phosphor bar code when a patient is exposed to an X-ray which is stored on the storage phosphor. Preferably, a portable x-ray source has a chart having sets of bar codes identifying x-ray examination type information. The bar code scanner scans the examination type bar codes at the time the x-ray of the patient is taken. The storage phosphor has a non-volatile read/write memory adhered to it. The bar code scanner has a memory probe which transfers the patient ID, storage phosphor ID and exam time information from the bar code scanner to the storage phosphor memory. The system includes a storage phosphor reader for converting an x-ray image stored in a storage phosphor into an x-ray image signal and for reading the bar code identification of the storage phosphor. The storage phosphor reader receives from the storage phosphor memory through an internal memory probe, information relating to patient identification, storage phosphor identification and examination type and matches the patient identification and examination type with the x-ray image signal.

FIELD OF THE INVENTION

This invention relates in general to storage phosphor radiography inwhich a latent x-ray image of a patient stored in a storage phosphor isconverted to an x-ray image signal. More particularly, the presentinvention relates to a storage phosphor radiography patientidentification system for matching patient x-ray exam data with thepatient's x-ray image.

BACKGROUND ART

In conventional film/screen radiography, a commonly used patientidentification system has the following features.

1. A requisition is filled out by the radiologist ordering a specificexam to be performed on a patient. The requisition is sent to theradiology department.

2. A technologist takes the requisition, an x-ray film cassette, and aportable x-ray generator to the patient bedside.

3. The technologist performs the exam and the film is exposed to x-rays.

4. The requisition is taped to the cassette and the exposed film istaken to the darkroom.

5. A preprinted information card is "flashed" on to the film. Suchinformation includes the patient name, medical record number, birthdate, hospital name, current date and other standard information.

6. The film is processed, and the radiology technologist verifies that a"good" image has been recorded.

7. A sticker is applied to the film which records the date, time ofexposure, technique, and technologist identification.

8. The finished x-ray film is placed on a light box for review anddiagnosis by a radiologist or physician.

Because of the inherent disadvantages of film radiography in theacquisition, storage and transmission of x-ray images, there has beenproposed a storage phosphor radiography system. Temporary x-ray imagesstored in a storage phosphor are converted into an x-ray image digitalsignal which can be stored, processed and transmitted. As described inU.S. Pat. No. Re. 31,847, reissued Mar. 12, 1985 to Luckey, aphotostimulable phosphor sheet is exposed to an image-wise pattern ofshort wavelength radiation, such as x-ray radiation, to record a latentimage pattern in the photostimulable phosphor sheet. The latent image isread out by stimulating the phosphor with a relatively long wavelengthstimulating radiation, such as red or infrared light. Upon stimulation,the stimulable phosphor releases emitted radiation of an intermediatewavelength, such as blue or violet light, in proportion to the quantityof x-ray radiation that was received. An x-ray image signal is producedby scanning the stimulable phosphor sheet in a raster pattern by meansof a beam of laser light deflected by an oscillating or rotatingscanning mirror. The emitted radiation is sensed by a photodetector toproduce an electrical x-ray image signal. This signal may then bestored, transmitted, or displayed on a monitor or reproduced as an x-rayfilm.

As with film-based radiography, storage phosphor radiography requiresthe matching of an x-ray image with the patient. In situations wheremany x-rays are taken, such as in an intensive care unit of a largehospital, the management of identification of x-rays with patients canbe monumental. In order to process an x-ray image signal as a functionof x-ray exposure conditions, it is also desirable to match x-rayexposure conditions and other patient identification data with the x-rayimage signal. Such matching results in proper diagnosis by adiagnostician (such as a radiologist) who views the x-ray image on amonitor or x-ray film reproduction.

In a known storage phosphor radiography system, patient information isentered into a workstation and is transferred to a magnetic card. (See,for example, U.S. Pat. No. 4,641,242, issued Feb. 3, 1987, inventorKimura; U.S. Pat. No. 4,739,480, issued Apr. 19, 1988, inventors Oona etal.; U.S. Pat. No. 4,885,468, issued Dec. 5, 1989, inventor Shimura.)After an x-ray exposure on a storage phosphor is made, a technicianplaces the cassette containing the exposed storage phosphor into areader and dumps the patient data into the reader by swiping themagnetic card through an associated magnetic card reader. Many problemsexist with this system, including double entry of patient data, which istypically entered into a computer at the time a patient is admitted intoa hospital. Moreover, the specific ordering of computed radiographycassettes and patient data must be maintained.

U.S. Pat. No. 4,960,994, issued Oct. 2, 1990, inventor Muller et al.,discloses a cassette which contains an x-ray film coated with astimulable phosphor layer and which has a cassette memory which isrigidly attached to the cassette. The memory carries storable,recordable, readable, and erasable data and is attached to the cassetteat a position spaced a predetermined distance from a given cassettecorner. The rigidly attached memory has four contacts for transfer ofdata and for power supply. This patent does not disclose the use of aseparate bar code on the cassette.

The health care bar code identification systems disclosed in thefollowing patents are not entirely suitable for use in storage phosphorradiography systems: U.S. Pat. No. 4,857,713, issued Aug. 15, 1989,inventor Brown; U.S. Pat. No. 5,006,699, issued Apr. 9, 1991, inventorsFelkner et al.; U.S. Pat. No. 4,835,372, issued May 30, 1989, inventorsGombrich et al.; and U.S. Pat. No. 4,857,372, issued Aug. 15, 1989,inventors Gombrich et al.

A storage phosphor radiography patient ID system using a hand-held barcode scanner has been proposed in commonly-assigned, copending U.S. Pat.application Ser. No. 963,036, filed Oct. 19, 1992. The disclosed systemrecords data using a hand-held bar code scanner. Because this image willbe recorded, processed, transmitted, and archived digitally by acomputer, the exam data also needs to be in digital form to travel withthe image. The exam data is read in directly from the bar code scannerby the storage phosphor reader into a header file which is associatedwith the image file. The image is quality assured by a radiology techusing an electronic view box(video monitor), and the image is printed onfilm with the necessary information by a laser printer. Thus, no"post-processing" is required.

A more recent development for use in healthcare identification systemsis suggested in the brochure entitled "Touch The Future", distributed byDallas Semiconductor, Dallas, Texas. A solid state read/write memory ina self contained stainless steel can has a self-adhesive backingattachable to a hospital bracelet to provide patient ID. A hospitalbedside testing application is also suggested in which the solid statememory container is adhered to a nurse's badge and a reagent cannister.A hand-held meter downloads the information received from these memoriesinto a personal computer. There is no suggestion in this brochure ofusing the solid state memory container in a storage phosphor radiographysystem.

A problem therefore exists in storage phosphor radiography apparatus oflinking examination information associated with an x-ray exam with thex-ray image recorded in a storage phosphor.

SUMMARY OF THE INVENTION

According to the present invention, there is provided a storage phosphorradiography identification system which provides a solution to theproblems of known film-based radiography and computed radiographyidentification systems. According to the present invention, a storagephosphor radiography patient identification system comprises:

patient identifying bar code means adapted to be located with a patientfor identifying a patient;

a storage phosphor cassette means for containing a storage phosphorwhich stores an x-ray image of a patient, said storage phosphor cassettemeans having storage phosphor identifying bar code means for identifyingsaid storage phosphor and further having adhered to it a read/writenon-volatile memory contained in a self adhesive electrically conductivecylindrical container;

x-ray examination type bar code means locatable with an x-ray source foridentifying x-ray examination type characteristics of an x-ray imagestored in said storage phosphor, wherein said x-ray examination type barcode means includes a first set of bar codes identifying unique bodyparts of a patient and a second set of bar codes identifying x-rayexposure conditions;

hand-held bar code scanner means, having memory, for scanning saidpatient identifying bar code means, said storage phosphor bar codeidentifying means, and a bar code from each of said respective sets ofsaid x-ray examination type bar code means at the time said storagephosphor means is exposed to an x-ray image of a patient, to producepatient identifying information, storage phosphor means identifyinginformation, and x-ray examination type information which is stored insaid memory; wherein said bar code scanner means is further providedwith a probe connected to said memory for transferring said identifyinginformation to said read/write non-volatile memory, adhered to saidstorage phosphor means;

storage phosphor reader means for converting a stored x-ray image insaid storage phosphor into an x-ray image signal, said storage phosphorreader means having, a) bar code reader means for reading said storagephosphor bar code identifying means to produce a storage phosphoridentifying signal matched with said x-ray image signal, and b) aread/write memory probe for contacting said read/write memory and fortransferring said identifying information stored in said memory to saidstorage phosphor reader for matching said transferred information tosaid x-ray image signal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a medical care facility incorporating anembodiment of the present invention;

FIG. 2 is a partially broken away perspective view of a storage phosphorcassette shown in FIG. 1;

FIG. 3 is a diagrammatic view of an x-ray exam type chart shown in FIG.1;

FIG. 4 is a diagrammatic view of a patient ID chart shown in FIG. 1;

FIG. 5 is a block diagram of the bar code scanner of FIG. 1;

FIG. 6 is a perspective view of a storage phosphor reader for readingstorage phosphors used in the system of the present invention;

FIG. 7 is a partial block diagram, partial diagrammatic view of thestorage phosphor reader shown in FIG. 6.

FIG. 8 is a partial perspective view of a storage phosphor cassetteshowing a read/write memory container adhered to a storage phosphor.

FIGS. 9 and 10 are respective top and side views of an exemplaryread/write memory for incorporation in the present invention.

FIG. 11 is a side view of a probe for transferring information to andfrom the memory of FIGS. 9 and 10 and incorporated in the storagephosphor reader of FIG. 7 and in the bar code scanner shown in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, there will be described an embodiment of thepresent invention as used in a multi-bed medical care facility such asthe intensive care unit of a hospital. As shown, the medical carefacility includes a plurality of beds 10, 12, 14, and 16 havingrespective patients 18, 20, 22, and 24 who require medical treatment. Aportable x-ray unit 26 has an x-ray source 28 mounted on a moveable arm30 supported by cabinet 32. Cabinet 32 includes controls and powersupply for x-ray source 28. Wheels 34 on cabinet 32 facilitate movingunit 26 from bed to bed.

According to the present invention, an x-ray image of a body part of apatient is produced in a stimulable storage phosphor contained in acassette. Thus, storage phosphor cassettes 36, 38, 40, and 42 areprovided for patients 18, 20, 22, and 24, respectively, Cassettes 36,38, 40, and 42 have storage phosphor identifying bar codes 44, 46, 48and 50 which uniquely identify each storage phosphor. Storage phosphorcassettes 36, 38, 40, and 42 also have adhered thereto respectiveread/write memories 37, 39, 41, and 45.

As shown in FIG. 2, storage phosphor cassette 42 has a removable storagephosphor plate 43 with bar code 50. Read/write memory 45 is shownadhered to cassette 42. FIG.8 shows an alternative placement for memory45' as adhered to storage phosphor plate 43. An exemplary storagephosphor cassette is disclosed in commonly assigned, copending U.S.application Ser. No. 617,121.

Each patient 18, 20, 22, and 24 is provided a unique patient identifyingbar code 52, 54, 56, and 58 on respective patient charts 60, 62, 64, and66. An alternative patient identifying bar code can also be placed on anidentifying bracelet placed on a patient's wrist.

X-ray unit 26 has associated with it a chart 68 having a list of x-rayexam types and/or x-ray exposure conditions with a set of bar codesidentifying each exam type and exposure condition. As shown in moredetail in FIG. 3, chart 68 has several sets 70A-70H of bar codes fordifferent types of exam information. These bar code sets areillustratively described as follows. Bar code set 70A identifies x-raysource Projections, such as, AP, Lateral, RLD, LLD, X-ray Table. Barcode set 70B identifies patient Body Part, such as Chest, Skull,Abdomen, CSpine, Pelvis, Extremity. Bar code set 70C identifies patientposition, such as, supine semi-erect, erect. Bar code set 70D identifiesx-ray source Distance to patient, such as 40 cm, 42 cm, 45 cm, 50 cm, 72cm. Bar code sets 70E and 70F identify x-ray source exposure parameters,respectively, kilovolts-KVP, (such as 50, 60, 70, 80, 85) andmilliamperes current-MAS (such as 1.25, 1.5, 2.5, 3.2, 50, 80). Bar codeset 70G identifies storage phosphor plate orientation, such as vertical,horizontal. Bar code set 70H identifies radiology technologist comments.

According to the technique of the present invention, an x-ray technicianwho is responsible for taking x-rays at the medical care facility isprovided with a portable bar code scanner 72. Bar code scanner 72 (seeFIG. 5) has a laser scanner 74 for scanning bar codes and converting thescanned bar code into an electrical signal which is stored in memory 76.Preferably, scanner 72 has a keyboard 78 for entering data which isstored in memory 76 and also has a display 80 for displaying the inputdata and other information. Control circuit 73, scanner 74, memory 76,display 80 and keypad 78 are internally connected by bus 82. Bar codescanner is also provided with a memory probe 75 connected to bus 82 fortransferring information from scanner 72 to a memory on a storagephosphor cassette, e.g., memory 45' on cassette 42 (FIG. 8).

At the time a patient is exposed to an x-ray, a technician scans thepatient identifying bar code, scans the storage phosphor identifying barcode and scans the bar code identifying the x-ray exam type. Thus, forexample, as shown in FIG. 1, x-ray source 28 is positioned over patient24 and storage phosphor cassette 42 is positioned under the chest areaof patient 24. At the time of taking an x-ray, the technician uses barcode scanner 72 to scan patient identifying bar code 66 on patient chart58, to scan storage phosphor identifying bar code 50 on storage phosphorcassette 42, and to scan x-ray examination type bar codes 70A-70H onexam type chart. A technician identifying bar code may also be read. Thetechnician can correct or manually enter data via keypad 78 at the timean x-ray exam is effected. The technician then transfers the examinformation from bar code scanner 72 to a memory 45' on the storagephosphor 43 of cassette 42.

After the technician has finished an x-ray exam of patient 24, he canmove x-ray unit 26 to the bedside of patients 18, 20, and 22 to producex-ray images in storage phosphor cassettes 36, 38, and 40.

After a set of x-ray exposures have been taken, relevant data for eachexposure scanned by portable bar code scanner 72, and the datatransferred form scanner 72 to the respective cassette memories 37, 39,41, 45, the technician carries the storage phosphor cassettes 36, 38,40, and 42 in a stack to a storage phosphor reader station. Such astation is shown in FIG. 6 and includes a storage phosphor reader 84 anda workstation 86. Preferably, a storage phosphor or cassette stacker(not shown) is provided adjacent to reader 84 to sequentially feedexposed storage phosphors into slot 90 of reader 84.

The exposed storage phosphor is read by reader 84 and converted to anx-ray image signal which is stored in a suitable memory. At the sametime, a bar code reader in reader 84 reads the storage phosphor bar codeand links the storage phosphor ID with the read x-ray image signal. Aseach storage phosphor is inserted into reader 84, and the stored x-rayimage is converted into an x-ray image signal, the storage phosphoridentifying bar code is read by a bar code reader in storage phosphorreader 84. Additionally, a memory probe in reader 84 transfers examinformation from the cassette read/write memory to reader 84 where it ismatched with the read x-ray image signal. Thus, the x-ray image signalread from a storage phosphor will be matched with the proper patient,x-ray exam type and other related information for further processing inworkstation 86. Workstation 86 includes keyboard 110 and monitor 112.

Referring now to FIG. 7, there is shown in more detail, storage phosphorreader 84. As shown, a storage phosphor 122 containing a storagephosphor plate 124 is loaded on cassette load platform 120. Load lever126 is rotated to clamp cassette 122 in place and unlatches the cassette122 by an extraction device 128. Extraction device is slidably mountedon translation stage 134 and includes hooks 136 which engage storagephosphor plate 124. Extraction device 128 extracts storage phosphorplate 124 from cassette 122 onto translation stage 134.

Translation stage 134 is slidably mounted on rails 140 and 142 formovement in opposite directions 144 which are perpendicular to thedirections 146 of loading and unloading of plate 124 relative totranslation stage 134. Translation stage 134 is driven by a screw motor150 mounted on block 152. Rails 140 and 142 are supported by framemember 154 of reader 84.

The laser scanning components will now be described. Reader 84 includesa laser 156 (such as a helium neon gas laser) for stimulation of storagephosphor plate 124. Laser 156 produces a laser beam 158 which passesthrough a shutter 160. Beam 158 is reflected off mirror 164 and passesthrough beam splitter 166 which directs a portion of the laser beam 158to reference photodetector 168. Following the beam splitter 166 laserbeam 158 passes through collimator 170. The collimated laser beam isdeflected by an oscillating scan mirror 172 driven by galvanometer 174.Scan mirror 172 provides the line scan raster motion of the laser beam158. Galvanometer 174 drives mirror 172 with a constant angularvelocity.

An f-theta lens 176 produces a flat field of focus and constant linearvelocity at the plane of storage phosphor plate 124. Folding mirror 178directs the laser beam through light collector 180 onto storage phosphorplate 124. Collector 180 may be of the type disclosed in commonlyassigned U.S. Pat. No. 5,151,592, issued Sep. 29, 1992, inventors Boutetet al. The stimulating light of laser beam 158 causes the storagephosphor in plate 124 to emit light (blue) which is a function of thex-ray image stored in plate 124. Collector 180 directs this emittedlight onto photomultiplier tube (PMT) 182. A filter 184 in front of theface of PMT 182 blocks the scattered stimulating laser light and passesthe light emitted by storage phosphor plate 124. Once a storage phosphorplate 24 is on translation stage 134 a scan is begun. From the homeposition of stage 134, it moves under collector 180. At this point,acquisition of the latent x-ray image on storage phosphor plate 124begins. At the end of the scan, translation stage 34 is returned to thehome position.

Immediately after translation, stage 34 reaches the home position, anerase lamp (not shown) is turned on. Following a predetermined erasetime (such as 30 seconds), the erase lamp is turned off and extractionmechanism 128 returns storage phosphor plate 124 in the direction ofarrow 146 to storage phosphor cassette 122. The storage phosphor readeruser can now rotate load lever 126 and remove cassette 122 from loadingplatform 120.

During the scan of storage phosphor plate 124, an emitted x-ray lightimage is converted by PMT 182 into an x-ray electrical current signal.This signal is converted to a digital image signal by amplifier ADC 186.

Patient identification and examination information are transferred intoreader 84 from memory probe 194. As each storage phosphor plate 124 isextracted from its cassette 122 cassette bar code reader 196 reads thebar code on plate 24. The image data and corresponding patient and examinformation are stored in memory 188 and correlated by computer 190.

The nonvolatile read/write memory is shown in FIGS. 9 and 10. As shown,memory 200 includes a cylindrical electrically conductive (such asstainless steel) container 202 which contains a non-volatile solid statememory. Can 202 has an adhesive backing 204 which mounts memory 200 to astorage phosphor cassette or storage phosphor plate. Memory 200 has aninner face 206 which is insulated from container 202. The rim 208 ofcontainer 202 is an electrical ground contact and face 206 is a datacontact. Data is transferred to and from memory 200 via the one-wireprotocol which needs only a single data contact and a ground return.

FIG. 10 shows a probe 210 which is adopted to engage memory 200. Probe210 includes a body 212 having a data contact face 214 and an electricalground rim 216 insulated from face 214. Wires 218,220 provide connectionto the system control.

Although the invention has been described with reference to preferredembodiments there, it will be understood that variations andmodifications can be effected with the spirit and scope of the inventionas described above as defined in the appended claims.

What is claimed is:
 1. A storage phosphor radiography patientidentification system comprising:patient identifying bar code meansadapted to be located with a patient for identifying a patient; astorage phosphor cassette means for containing a storage phosphor whichstores an x-ray image of a patient, said storage phosphor cassette meanshaving storage phosphor identifying bar code means for identifying saidstorage phosphor and further having adhered to it a read/writenon-volatile memory contained in a self adhesive electrically conductivecylindrical container; x-ray examination type bar code means locatablewith an x-ray source for identifying x-ray examination typecharacteristics of an x-ray image stored in said storage phosphor,wherein said x-ray examination type bar code means includes a first setof bar codes identifying unique body parts of a patient and a second setof bar codes identifying x-ray exposure conditions; hand-held bar codescanner means, having memory, for scanning said patient identifying barcode means, said storage phosphor identifying bar code means, and a barcode from each of said first and second sets of said x-ray examinationtype bar code means at the time said storage phosphor means is exposedto an x-ray image of a patient, to produce patient identifyinginformation, storage phosphor identifying information, and x-rayexamination type information which is stored in said memory; whereinsaid bar code scanner means is further provided with a probe, connectedto said memory for transferring the identifying information to saidread/write non-volatile memory, adhered to said storage phosphor means;storage phosphor reader means for converting a stored x-ray image insaid storage phosphor into an x-ray image signal, said storage phosphorreader means having, a) bar code reader means for reading said storagephosphor bar code identifying means to produce a storage phosphoridentifying signal matched with said x-ray image signal, and b) aread/write memory probe for contacting said read/write memory and fortransferring said identifying information stored in said memory to saidstorage phosphor reader means for matching said transferred informationto said x-ray image signal.